In a dry cleaning plant, clothes and other fabric articles are cleaned in machines using a dry cleaning solvent for example perchlorethylene which is commonly referred to as "perc". When the solvent has been used for cleaning, it must be filtered to remove dirt, lint and other contaminants, the filtered solvent being returned to the machine. Filtering is customarily effected by apparatus using filter cartridges through which the solvent is passed. After filter cartridges have been used for a period of time, they must be replaced. However, before being discarded, the used cartridges must be stripped of solvent remaining in them not only to conserve the solvent but further because environmental restrictions prohibit the disposal of filter cartridges containing solvent.
Even though it is continually filtered, the solvent must be periodically distilled in order to remove impurities that are not removed by filtering. In the distillation process, the solvent is in effect boiled or vaporized. The solvent vapor--usually together with steam--is thereupon condensed and the water and solvent of the resulting condensate are separated from one another by gravity since the solvent is heavier than water.
A further problem that arises in dry cleaning plants is the control of vapor or fumes from the volatile solvent. After clothes or other articles have been dry cleaned, they are tumbled in a drying tumber or reclaimer with hot air to remove most of the solvent from the garments. The air from the tumbler or reclaimer containing residual solvent vapor cannot be discharged into the atmosphere, not only because of pollution problems, but also because this would result in an unacceptable loss of solvent. It is therefore a passed through an adsorber comprising a housing containing activated carbon pellets which adsorb the solvent. After the carbon pellets have become saturated with solvent, they are desorbed by passing steam through the adsorber to drive off solvent, the resulting vapor together with the steam being condensed in a condenser and the condensate being thereafter fed to a solvent-water separator.
There are presently separate pieces of apparatus for filtering the solvent, stripping filter cartridges, distilling the solvent and adsorbing the solvent vapor. However, the use of such apparatus not only involves considerable purchase, installation and maintenance expense but is also uneconomical of floor space, thereby further increasing the expense of the dry cleaning plant.